QSFP double density module

Abstract

An optical transceiver may include pairs of lasers, each laser of a particular pair generating light at the same wavelength and each pair of lasers generating light at different wavelengths. The light from the lasers may be demultiplexed onto a pair of outputs, with each output receiving light from different lasers of each pair of lasers.

What is claimed is: 
     
       1. An optical transceiver, comprising:
 a plurality of pairs of laser diodes wherein each of the plurality of pairs of laser diodes is mounted on a separate chip, is configured to generate light at a different wavelength, and includes a first laser diode and a second laser diode where the first laser diode and the second laser diode of each of the plurality of pairs of laser diodes are configured to generate light at a same wavelength; 
 a Planar Lightwave Circuit (PLC) having a first transmit output and a second transmit output; 
 a first optical multiplexer in the PLC configured to receive light from the first laser diode of each of the plurality of pairs of laser diodes and to present the light received from the first laser diode of each of the plurality of pairs of laser diodes to the first transmit output of the PLC; and 
 a second optical multiplexer in the PLC configured to receive light from the second laser diode of each of the plurality of pairs of laser diodes and to present the light received from the second laser diode of each of the plurality of pairs of laser diodes to the a second transmit output of the PLC. 
 
     
     
       2. The optical transceiver of  claim 1  further comprising:
 a plurality of lens wherein each of the plurality of lens couple light for one of the laser diodes in the plurality of pairs of laser diodes to the PLC. 
 
     
     
       3. The optical transceiver of  claim 2  wherein each of the plurality of lenses is associated with a MEMS device where the MEMS device is configured to adjust the position of an associated lens. 
     
     
       4. The optical transceiver of  claim 3  wherein the MEMS device comprises:
 a holder that is configured to hold the associated lens; and 
 a first arm and a second arm coupled to holder to position the associated lens to pass light from one of the laser diodes of the plurality of pairs of laser diodes to an input of one of the first and second optical mulitplexers in the TLC. 
 
     
     
       5. The optical transceiver of  claim 1  further comprising:
 a plurality of Monitoring PhotoDiodes (MPDs) that receive light from laser diodes in the plurality of pairs of laser diodes and monitor the power of the laser diodes. 
 
     
     
       6. The optical transceiver of  claim 5  wherein the first and second multiplexers are provided by an Array Waveguide Grating (AWG). 
     
     
       7. The optical transceiver of  claim 6  further comprising:
 a plurality of waveguide branches that provide light generated by the laser diodes in the plurality of pairs of laser diodes from the AWG to the plurality of MPDs. 
 
     
     
       8. The optical transceiver of  claim 6  further comprising:
 a plurality of greyscale mirrors positioned in the waveguides of the AWG to reflect light generated by the laser diodes in the plurality of pairs of laser diodes from the AWG to the plurality of MPDs. 
 
     
     
       9. The optical transceiver of  claim 1  further comprising:
 a plurality of photodiodes wherein each of the plurality of photodiodes is configured to convert light of a particular wavelength to electrical signals; 
 a first optical demultiplexer that is configured to receive light comprised of a plurality of wavelengths from a first input source, separate the received light into light of each of the plurality of wavelengths, and provide the light of each particular one of the plurality of wavelengths to one of the plurality of photodiodes that converts the particular one of the plurality of wavelengths into electrical signals; and 
 a second optical demultiplexer that is configured to receive light comprised of a plurality of wavelengths from a second input source, separate the received light into light of each of the plurality of wavelengths, and provide the light of each particular one of the plurality of wavelengths to one of the plurality of photodiodes that converts the particular one of the plurality of wavelengths into electrical signals. 
 
     
     
       10. The optical transceiver of  claim 9  wherein the first and second optical demultiplexers are in the PLC where the first optical demultiplexer receives light from a first receive input of the PLC and the second optical demultiplexer receive light from a second receive input of the PLC. 
     
     
       11. The optical transceiver of  claim 9  further comprising:
 a plurality of TransImpedance Amplifiers (TIA) where each of the plurality of TIAs is wirebonded to a one of the plurality of photodiodes. 
 
     
     
       12. The optical transceiver of  claim 11  wherein the first and second multiplexers are provided by an Array Waveguide Grating (AWG) in the PLC. 
     
     
       13. The optical transceiver of  claim 11  further comprising:
 a plurality of grayscale mirror mounted in the PLC to reflect light from the first and second demulitplexers to the plurality of photodiodes. 
 
     
     
       14. A method for transmitting signals using an optical transceiver, comprising:
 generating light at a plurality of different wavelengths using a plurality of pairs of laser diodes wherein each of the plurality of laser diodes is mounted is mounted on a separate chip and configured to generate light at a different wavelength and each of the plurality of pairs of laser diodes includes a first laser diode and a second laser diode where the first laser diode and the second laser diode of each of the plurality of pairs of laser diodes are configured to generate light at a same wavelength; 
 receiving light from the first laser diode of each of the plurality of pairs of laser diodes in a first optical multiplexer; 
 multiplexing the light received of the first laser diode of each of the plurality of pairs of laser diodes from the first optical multiplexer onto a first transmit output of a PLC; and 
 receiving light from the second laser diode of each of the plurality of pairs of laser diodes in a second optical multiplexer; 
 multiplexing the light received of the second laser diode of each of the plurality of pairs of laser diodes from the second optical multiplexer onto a first transmit output of a PLC. 
 
     
     
       15. The method of  claim 14  further comprising:
 coupling the light from one of the laser diodes in the plurality of pairs of laser diodes to the PLC using one of a plurality of lenses. 
 
     
     
       16. The method of  claim 15  further comprising:
 adjusting a position of one of the plurality of lenses a MEMS device. 
 
     
     
       17. The method of  claim 14  further comprising:
 receiving light from laser diodes in the plurality of pairs of laser diodes in a plurality of Monitoring PhotoDiodes (MPDs); and 
 monitoring the power of the laser diodes using the plurality of MPDs. 
 
     
     
       18. The method of  claim 17  wherein the first and second multiplexers are provided by an Array Waveguide Grating (AWG) and the method further comprises:
 providing light generated by the laser diodes in the plurality of pairs of laser diodes from the AWG to the plurality of MPDs using a plurality of waveguide branches. 
 
     
     
       19. The method of  claim 17  wherein the first and second multiplexers are provided by an Array Waveguide Grating (AWG) and the method further comprises:
 reflecting light generated by the laser diodes in the plurality of pairs of laser diodes from the AWG to the plurality of MPDs using a plurality of greyscale mirrors positioned in the waveguides of the AWG. 
 
     
     
       20. The method of  claim 14  further comprising:
 receiving light comprised of a plurality of wavelengths from a first input source in a first optical demultiplexer; 
 separating the received light into light of each of the plurality of wavelengths using the first optical demulitplexer; 
 providing the light of each particular one of the plurality of wavelengths from the first optical demultiplexer to one of a plurality of photodiodes that converts the particular one of the plurality of wavelengths into electrical signals; 
 receiving light comprised of a plurality of wavelengths from a second input source in a second optical demultiplexer; 
 separating the received light into light of each of the plurality of wavelengths using the second optical demulitplexer; 
 providing the light of each particular one of the plurality of wavelengths from the second optical demultiplexer to one of a plurality of photodiodes that converts the particular one of the plurality of wavelengths into electrical signals; and 
 converting the received light of a particular wavelength to electrical signals in each one of the plurality of photodiodes.